Armchair



FIG. 1 is a front perspective view of an armchair showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a side view thereof; and,

FIG. 6 is a rear view thereof. 

The ornamental design for an armchair, as shown and described. 